package com.spice.service.config;/*
 * 导出列的自适应宽度
 * */


//在导出时注册registerWriteHandler(new CustomCellWriteHandler())

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.enums.CellDataTypeEnum;
import com.alibaba.excel.metadata.CellData;
import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.util.CollectionUtils;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.style.column.AbstractColumnWidthStyleStrategy;
import com.spice.service.entity.pojo.ShapeDesc;
import org.apache.poi.ss.usermodel.Cell;

import java.io.File;
import java.util.*;

public class CustomCellWriteHandler extends AbstractColumnWidthStyleStrategy {
    private static final int MAX_COLUMN_WIDTH = 255;
    private Map<Integer, Map<Integer, Integer>> CACHE = new HashMap(8);

    public CustomCellWriteHandler() {
    }

    protected void setColumnWidth(WriteSheetHolder writeSheetHolder, List<CellData> cellDataList, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {
        boolean needSetWidth = isHead || !CollectionUtils.isEmpty(cellDataList);
        if (needSetWidth) {
            Map<Integer, Integer> maxColumnWidthMap = (Map) CACHE.get(writeSheetHolder.getSheetNo());
            if (maxColumnWidthMap == null) {
                maxColumnWidthMap = new HashMap(16);
                CACHE.put(writeSheetHolder.getSheetNo(), maxColumnWidthMap);
            }

            Integer columnWidth = this.dataLength(cellDataList, cell, isHead);
            if (columnWidth >= 0) {
                if (columnWidth > 255) {
                    columnWidth = 255;
                }

                Integer maxColumnWidth = (Integer) ((Map) maxColumnWidthMap).get(cell.getColumnIndex());
                if (maxColumnWidth == null || columnWidth > maxColumnWidth) {
                    ((Map) maxColumnWidthMap).put(cell.getColumnIndex(), columnWidth);
                    writeSheetHolder.getSheet().setColumnWidth(cell.getColumnIndex(), columnWidth * 256);
                }

            }
        }
    }

    private Integer dataLength(List<CellData> cellDataList, Cell cell, Boolean isHead) {
        if (isHead) {
            return cell.getStringCellValue().getBytes().length;
        } else {
            CellData cellData = (CellData) cellDataList.get(0);
            CellDataTypeEnum type = cellData.getType();
            if (type == null) {
                return -1;
            } else {
                switch (type) {
                    case STRING:
                        return cellData.getStringValue().getBytes().length + 100;
                    case BOOLEAN:
                        return cellData.getBooleanValue().toString().getBytes().length + 100;
                    case NUMBER:
                        return cellData.getNumberValue().toString().getBytes().length + 100;
                    default:
                        return -1;
                }
            }
        }
    }

    public static void main(String[] args) {
        //将前端页面上想要导出的excel文件字段名通过查数据库中的表信息来进行动态的导入数据信息
        List<ShapeDesc> shapeDescList = new ArrayList<>();
        shapeDescList.add(new ShapeDesc("1", "a", "1s", "1s", "1s"));

        String fileName = new File("resources/test.xlsx").getAbsolutePath();
        //文件导出为.xls文件
        EasyExcel.write(fileName, ShapeDesc.class)
                .registerWriteHandler(new CustomCellWriteHandler())
                .sheet("")
                .doWrite(shapeDescList);

    }
}
